Morphological clues to wet granular pile stability
Morphological clues to wet granular pile stability
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DOI：
10.1038/nmat2117
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发表时间：
2008-03-01
期刊：
影响因子：
41.2
通讯作者：
Herminghaus, S.
中科院分区：
文献类型：
--
作者：
Scheel, M.;Seemann, R.;Herminghaus, S.
当沙子等粒状材料与一定量的液体混合时，后者的表面张力赋予材料相当大的硬度，从而可以雕刻沙堡等(1-4)。颗粒堆内液体界面的几何形状非常复杂，并且随液体含量的变化而强烈变化(5-7)。令人惊讶的是，堆的机械性能在很大范围内（14-16）很大程度上与液体量（2,8-13）无关。我们借助 X 射线显微断层扫描解决了这个难题，表明机械性能对液体含量的显着不敏感是由于堆中液体的特殊组织成开放结构。对于球形颗粒，建立了一个简单的几何规则，将宏观特性与内部液体形态联系起来。我们提供的证据表明这个概念对于具有非球形颗粒的系统也有效。因此，我们的结果为理解包括滑坡在内的各种湿颗粒系统的复杂物理以及混合和团聚问题提供了新的见解。
When a granular material such as sand is mixed with a certain amount of liquid, the surface tension of the latter bestows considerable stiffness to the material, which enables, for example, sand castles to be sculpted(1-4). The geometry of the liquid interface within the granular pile is of extraordinary complexity and strongly varies with the liquid content(5-7). Surprisingly, the mechanical properties of the pile are largely independent of the amount of liquid(2,8-13) over a wide range(14-16). We resolve this puzzle with the help of X-ray microtomography, showing that the remarkable insensitivity of the mechanical properties to the liquid content is due to the particular organization of the liquid in the pile into open structures. For spherical grains, a simple geometric rule is established, which relates the macroscopic properties to the internal liquid morphologies. We present evidence that this concept is also valid for systems with non-spherical grains. Hence, our results provide new insight towards understanding the complex physics of a large variety of wet granular systems including land slides, as well as mixing and agglomeration problems.